[jira] [Commented] (CALCITE-4063) Unnest an array of structs causes ClassCastException

["Ruben Q L (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-4063?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17134302#comment-17134302 ] 

Ruben Q L commented on CALCITE-4063:
------------------------------------

The issue might be on the UNNESTing of a simple ROW, which returns an array instead of a value.
{code:sql}
select * from UNNEST(array[ROW(3), ROW(4)]) as T2(y)
-- y=[3]  => should it be y=3 ???
-- y=[4]  => should it be y=4 ???
{code}

If we compare it with a similar query with a "complex" ROW, the problem does not occur:
{code:sql}
select * from UNNEST(array[ROW(3, 3), ROW(4, 4)]) as T2(y, z)
-- y=3; z=3
-- y=4; z=4

select * from (values (1), (2)) T1(x), UNNEST(array[ROW(3, 3), ROW(4, 4)]) as T2(y, z)
-- x=1; y=3; z=3
-- x=1; y=4; z=4
-- x=2; y=3; z=3
-- x=2; y=4; z=4
{code}

> Unnest an array of structs causes ClassCastException
> ----------------------------------------------------
>
>                 Key: CALCITE-4063
>                 URL: https://issues.apache.org/jira/browse/CALCITE-4063
>             Project: Calcite
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 1.23.0
>            Reporter: Ruben Q L
>            Priority: Major
>
> If we run the following queries with UNNEST operator, we get the expected results:
> {code:sql}
> select * from UNNEST(array[3, 4]) as T2(y);
> -- y=3
> -- y=4
> select * from UNNEST(array[array[3], array[4]]) as T2(y)
> -- y=[3]
> -- y=[4]
> select * from UNNEST(array[ROW(3), ROW(4)]) as T2(y)
> -- y=[3]
> -- y=[4]
> {code}
> However, if we try to combine them with a correlation with some other values, as we could do in more realistic examples: 
> {{select * from dept_nested as d, UNNEST(d.employees) e2}}
> The first two return the expected results, but the last one throws an exception:
> {code:sql}
> select * from (values (1), (2)) T1(x), UNNEST(array[3, 4]) as T2(y);
> -- x=1; y=3
> -- x=1; y=4
> -- x=2; y=3
> -- x=2; y=4
> select * from (values (1), (2)) T1(x), UNNEST(array[array[3], array[4]]) as T2(y);
> -- x=1; y=[3]
> -- x=1; y=[4]
> -- x=2; y=[3]
> -- x=2; y=[4]
> select * from (values (1), (2)) T1(x), UNNEST(array[ROW(3), ROW(4)]) as T2(y);
> -- ERROR!!!
> -- java.lang.ClassCastException: org.apache.calcite.runtime.FlatLists$Flat1List cannot be cast to java.lang.Integer
> {code}



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